Download Environmental science

Chapter 1
An Introduction
to Environmental
Science
Copyright © 2009 Benjamin Cummings is an imprint of Pearson
Environment: the total of our surroundings
• All the things around us with which we
interact:
• Living things
• Animals, plants, forests, fungi, etc.
• Non-living things
• Continents, oceans, clouds, soil, rocks
• Our built environment
• Buildings, human-created living
centers
• Social relationships and institutions
Copyright © 2009 Benjamin Cummings is an imprint of Pearson
Humans exist within the environment
• Humans exist within the environment and are part of
nature.
Copyright © 2009 Benjamin Cummings is an imprint of Pearson
Humans and the world around us
• Humans depend completely on the environment for survival.
• But natural systems have been degraded
- Pollution, erosion, and species extinction
- Environmental changes threaten long-term health and
survival.
• Environmental science is the study of:
- How the natural world works
- How the environment affects humans and vice versa
• With environmental problems come opportunities for solutions.
Copyright © 2009 Benjamin Cummings is an imprint of Pearson
Natural resources: vital to human survival
Natural resources = substances and energy sources needed for
survival
• Renewable resources:
- Perpetually available: sunlight, wind, wave energy
- Renew themselves over short periods of time: timber, water,
soil
- These can be destroyed
• Non-renewable resources: can be depleted
- Oil, coal, minerals
Copyright © 2009 Benjamin Cummings is an imprint of Pearson
Global human population growth
• More than 6.7 billion humans
• Why so many humans?
- Agricultural revolution
- Stable food supplies
- Industrial revolution
- Urbanized society
powered by fossil fuels
- Sanitation and
medicines
- More food
Copyright © 2009 Benjamin Cummings is an imprint of Pearson
Thomas Malthus and human population
• Thomas Malthus
• Population growth must be
controlled, or it will
outstrip food production.
• Starvation, war, disease
• Neo-Malthusians
• Population growth has
disastrous effects.
• Paul and Anne Ehrlich, The
Population Bomb (1968)
• Agricultural advances have
only postponed crises.
Copyright © 2009 Benjamin Cummings is an imprint of Pearson
Resource consumption exerts impacts
• Garret Hardin’s “tragedy of the commons” (1968)
• Unregulated exploitation causes resource depletion
• Grazing lands, forests, air, water
• No one has the incentive to care for a resource.
• Everyone takes what he or she can until the resource
is depleted.
• Solution?
• Private ownership?
• Voluntary organization to enforce responsible use?
• Governmental regulations?
Copyright © 2009 Benjamin Cummings is an imprint of Pearson
The “ecological footprint”
• The environmental impact of a
person or population
- Amount of biologically
productive land + water
- For resources and to
dispose/recycle waste
• Overshoot: humans have
surpassed the Earth’s capacity to
support us
We are using 30% more of the planet’s resources than
are available on a sustainable basis!
Copyright © 2009 Benjamin Cummings is an imprint of Pearson
Environmental science
• Can help us avoid mistakes made by past civilizations
- Human survival depends on how we interact with our
environment.
- Our impacts are now global.
- Many great civilizations have fallen after depleting their
resources.
The lesson of Easter Island:
people annihilated their
culture by destroying their
environment. Can we act
more wisely to conserve our
resources?
Copyright © 2009 Benjamin Cummings is an imprint of Pearson
Environmental science: how the natural
world works
Environment  impacts  Humans
• Its goal: developing solutions to
environmental problems
• An interdisciplinary field
-Natural sciences: information about the
natural world
- Environmental Science programs
-Social sciences: study human interactions
and behavior
- Environmental Studies programs
Copyright © 2009 Benjamin Cummings is an imprint of Pearson
Environmental science is not
environmentalism
•Environmental science
• The pursuit of knowledge
about the natural world
• Scientists try to remain
objective
•Environmentalism
• Environmental activism
• A social movement dedicated
to protecting the natural world
Copyright © 2009 Benjamin Cummings is an imprint of Pearson
The nature of science
• Science:
- A systematic process for learning about the world and
testing our understanding of it
- The accumulated body of knowledge that results from
a dynamic process of observation, testing, and
discovery
• Science is essential:
- To sort fact from fiction
- Develop solutions to the problems we face
Copyright © 2009 Benjamin Cummings is an imprint of Pearson
Applications of science
Policy decisions and
management practices
Technology
Energy-efficient methanolpowered fuel cell car from
DaimlerChrysler
Restoration of forest ecosystems altered
by human suppression of fire
Copyright © 2009 Benjamin Cummings is an imprint of Pearson
The scientific method
• A technique for testing ideas
• A scientist makes an observation and
asks questions of some phenomenon.
• The scientist formulates a hypothesis, a
statement that attempts to answer the
question.
• The hypothesis is used to generate
predictions: specific statements that can
be tested.
• The results support or reject the
hypothesis.
Copyright © 2009 Benjamin Cummings is an imprint of Pearson
Testing predictions
• Experiment: an activity that tests the validity of a hypothesis
• Variables: conditions that can be manipulated and/or measured
- Independent variable: a condition that is manipulated
- Dependent variable: a variable that is affected by the
manipulation of the independent variable
• Controlled experiment: one in which all variables are controlled
- Control: the unmanipulated point of comparison
- Treatment: the manipulated point of comparison
• Data: information that is generally quantitative (numerical)
Copyright © 2009 Benjamin Cummings is an imprint of Pearson
Experiments test the validity of a hypothesis
• Manipulative experiments yield the strongest evidence
- Provides the strongest type of evidence
- Reveal causal relationships: changes in independent variables
cause changes in dependent variables
- But many things can’t be manipulated: long-term or largescale questions (i.e., global climate change)
• Natural experiments show real-world complexity
- Only feasible approach for ecosystem or planet-scale
- Results are not so neat and clean, so answers aren’t simply
black and white
Copyright © 2009 Benjamin Cummings is an imprint of Pearson
The scientific process is part of a larger process
Peer-review: other scientists provide comments and criticism
• Guards against faulty science
• Conference presentations improve the quality of the science
• Scientists interact with their colleagues
• Grants and funding come from private or government
agencies.
• Can lead to conflict of interest if the data show the funding
source in an unfavorable light
• The scientist may be reluctant to publish or doctor the
results.
Copyright © 2009 Benjamin Cummings is an imprint of Pearson
Ethical standards
• Ethical standards: criteria that help differentiate right
from wrong
- Classical standard = virtue
- The golden rule: treat others as you want to be treated
- Utility: something right produces the most benefits for
the most people
Copyright © 2009 Benjamin Cummings is an imprint of Pearson
Environmental ethics
• Environmental ethics: application of ethical standards to
relationships between human and non-human entities
- Hard to resolve; depends on the person’s ethical
standards
- Depends on the person’s domain of ethical concern
Should we conserve
resources for future
generations?
Should we drive other
species to extinction?
Copyright © 2009 Benjamin Cummings is an imprint of Pearson
Is is OK to destroy a
forest to create jobs
for people?
Is it OK for some
communities to be exposed
to excess pollution?
Three ethical perspectives
• Anthropocentrism: only humans have rights
- Costs and benefits are measured only according to their impact
on people
- Anything not providing benefit to people has no value
• Biocentrism: certain living things also have value
- All life has ethical standing
- Development is opposed if it destroys life, even if it creates jobs
• Ecocentrism: whole ecological systems have value
- Values the well-being of species, communities, or ecosystems
- Holistic perspective, stresses preserving connections
Copyright © 2009 Benjamin Cummings is an imprint of Pearson
Expanding ethical consideration
Copyright © 2009 Benjamin Cummings is an imprint of Pearson
The preservation ethic
• Unspoiled nature should be protected for its own inherent value.
• We should protect our environment in a pristine state, because it
promotes human happiness and fulfillment.
• John Muir (right, with President Roosevelt at Yosemite National
Park) had an ecocentric viewpoint.
Copyright © 2009 Benjamin Cummings is an imprint of Pearson
The conservation ethic
• Use natural resources wisely for the greatest good for the most
people
• A utilitarian standard that calls for prudent, efficient, and
sustainable resource extraction and use
• Gifford Pinchot had an anthropocentric viewpoint.
Copyright © 2009 Benjamin Cummings is an imprint of Pearson
The land ethic
• Healthy ecological systems depend on protecting all parts.
• Aldo Leopold believed that humans should view themselves
and the land as members of the same community.
• We are obligated to treat the land ethically.
• The land ethic will help guide decision making.
Copyright © 2009 Benjamin Cummings is an imprint of Pearson
Sustainability
• A guiding principle of environmental science
• Living within our planet’s means
- The Earth can sustain humans AND other organisms
for the future
- Leaving our descendents with a rich, full world
- Developing solutions that work in the long term
- Requires keeping fully functioning ecological systems
Copyright © 2009 Benjamin Cummings is an imprint of Pearson
Sustainability
• We are increasing our burden on the planet each year.
- Population growth, affluence, consumption
• Natural capital: the accumulated wealth of Earth
- We are withdrawing our planet’s natural capital 30%
faster than it is being produced
Copyright © 2009 Benjamin Cummings is an imprint of Pearson
We are increasing our burden on the planet
• Human population growth amplifies all environmental
problems
- The growth rate has slowed, but we still add over
200,000 people to the planet each day.
• Our consumption of resources has risen even faster.
- Life has become more pleasant for us so far.
- However, rising consumption increases the demands
we make on our environment.
- The rise in affluence has not been equal. The gap
between rich and poor has doubled in the past 40
years.
Copyright © 2009 Benjamin Cummings is an imprint of Pearson
Ecological footprints are not all equal
• The ecological footprints of
countries vary greatly.
- The U.S. footprint is much
greater than the world’s
average.
- Developing countries have
much smaller footprints
than developed countries.
Copyright © 2009 Benjamin Cummings is an imprint of Pearson
The 2005 Millennium Ecosystem Assessment
•
The most comprehensive scientific assessment of the
condition of the world’s ecological systems
•
Major findings:
•
Humans have drastically altered ecosystems.
•
These changes have contributed to human wellbeing and economic development, but at a cost.
•
Environmental degradation could get much worse.
•
Degradation can be reversed, but it requires work.
Copyright © 2009 Benjamin Cummings is an imprint of Pearson
Sustainable solutions abound
• Sustainable development: using resources to satisfy current needs
without compromising future availability of resources
• Sustainability involves:
- Renewable energy sources
- Soil conservation, high-efficiency irrigation, organic agriculture
- Pollution reduction
- Habitat and species protection
- Recycling
- Fighting global climate change
Humanity’s challenge is to develop solutions that further our
quality of life while protecting and restoring the environment.
Copyright © 2009 Benjamin Cummings is an imprint of Pearson
Will we develop in a sustainable way?
• Sustainable solutions must
meet:
- Environmental goals
- Economic goals
- Social goals
• Requires that humans limit our
impact while promoting
economic well-being and social
equity
- Apply science to solve
problems
The single most important question we face is: "Will we
develop sustainably?”
Copyright © 2009 Benjamin Cummings is an imprint of Pearson
Conclusion
• Finding ways to live sustainably on Earth requires a solid
ethical grounding and scientific understanding of our
natural and social systems.
• Environmental science helps us understand our
relationship with the environment and informs our
attempts to solve and prevent problems.
• Identifying a problem is the first step in solving it.
• Solving environmental problems can move us toward
health, longevity, peace, and prosperity.
- Environmental science can help find balanced
solutions to environmental problems.
Copyright © 2009 Benjamin Cummings is an imprint of Pearson